以聚乙二醇为模板凝胶转化制备介孔ZSM-5沸石及其催化性能

doi:10.15541/jim20150180

摘要/Abstract

摘要：

以聚乙二醇为介孔导向剂, 通过凝胶转化制备了介孔ZSM-5沸石。研究表明, 在TPA⁺/SiO₂=0.1时经过9~15 h溶剂挥发制得的凝胶, 在160℃处理24 h可得到介孔ZSM-5沸石; 挥发时间太短或太长会得到纯的ZSM-5沸石或介孔材料, 说明在凝胶的制备过程中, 通过控制溶剂的挥发程度, 既可为沸石生长过程提供所需的水分, 又能避免沸石晶体形成过程中无定型相的产生, 从而在较低的TPA⁺浓度下获得介孔ZSM-5沸石。与传统的ZSM-5沸石相比, 利用该方法制备的介孔ZSM-5沸石不仅具有微孔/介孔多级孔结构, 同时具有沸石材料较强的酸性、较高的水热稳定性和择形催化性能, 使其在苯甲醛与正丁醇的大分子醇醛缩聚反应中能有效地克服传统沸石孔径限制的缺点, 收率高达42.4%。

关键词: 介孔沸石, 聚乙二醇, 凝胶转化, 一锅法

Abstract:

A simple strategy for synthesizing mesoporous zeolite ZSM-5 via gel conversion was successfully developed with polyethyleneglycol as mesopore directing agent. It is revealed that the gel obtained after 9-15 h evaporation of solvents could be transferred into mesoporous ZSM-5 zeolite after treatment at 160℃ for 24 h. However, pure ZSM-5 zeolite or mesoporous silica was achieved with too short or too long evaporation periods. The results indicate that the gelation process through solvent evaporation controls the hierarchical structure formation kinetically, which not only provides an appropriate amount of water for zeolite crystallization, but also prevents the phase-separation between zeolite and amorphous phases. Due to the introduction of the mesoporosity of several tens of nanometers in size, this hierarchical micro/mesostructured zeolite exhibits enhanced catalytic activities in the large molecules involved reactions, including aldol condensation of benzaldehyde with n-butyl alcohol and Pechmann reaction of resorcinol with ethylacetoacetate.

Key words: mesoporous zeolite, polyethyleneglycol, gel conversion, one-pot

中图分类号:

O611

安建国, 高翔, 金军江, 顾金楼, 李亮, 李永生, 施剑林. 以聚乙二醇为模板凝胶转化制备介孔ZSM-5沸石及其催化性能[J]. 无机材料学报, 2015, 30(11): 1148-1154.

AN Jian-Guo, GAO Xiang, JIN Jun-Jiang, GU Jin-Lou, LI Liang, LI Yong-Sheng, SHI Jian-Lin. Mesoporous Zeolite ZSM-5 Synthesized via Gel Conversion with Polyethyleneglycol as Template and Its Catalytic Performance[J]. Journal of Inorganic Materials, 2015, 30(11): 1148-1154.

图/表 11

图1 传统ZSM-5和MZ-X样品的XRD图谱

Fig. 1 XRD patterns of conventional ZSM-5 and MZ-X samples

图2 MZ-X系列样品的氮气吸附脱附等温线(a)和MZ-9样品和传统ZSM-5的氮气吸附脱附等温线以及MZ-9脱附曲线对应的BJH孔径分布图(b)

Fig. 2 (a) N2 adsorption-desorption isotherms of MZ-X samples and (b) N2 adsorption-desorption isotherms of conventional ZSM-5 and MZ-9 with the pore-size distribution curve of MZ-9 (inset)

表1 不同样品的孔结构参数[a]

Table 1 Textural properties of the samples

Sample	Gel weight loss /%	S_BET /(m²·g^-1)	S_external /(m²·g^-1)	V_total /(cm³·g^-1)	V_micro /(cm³·g^-1)	V_external /(cm³·g^-1)	Pore size /nm
MZ-0	95	385	85	0.18	0.12	0.06	-
MZ-9	87	441	172	0.30	0.11	0.19	10-50
MZ-15	82	469	365	0.60	0.06	0.54	10-40
MZ-21	64	603	603	1.36	0	1.36	5-15
Conventional ZSM-5	-	395	98	0.18	0.11	0.07	-

图3 MZ-0(a)、MZ-9(b, c)、MZ-15(d)和MZ-21(e, f)样品的扫描电镜照片

Fig. 3 SEM images of MZ-0 (a), MZ-9 (b, c), MZ-15 (d) and MZ-21 (e, f)

图4 MZ-9样品在不同倍率下的透射电镜照片(a, b)和(b)图中白色矩形区域的高分辨透射电镜照片(c)以及(c)图对应的选区电子衍射结果(d)

Fig. 4 TEM images of MZ-9 at different magnifications (a, b) and HR-TEM images from the area marked by a white square in b (c), as well as selected area electron diffraction (SAED) corresponded to c (d)

图5 MZ-9样品的29Si(a)和27Al(b)核磁共振谱

Fig. 5 29Si (a) and 27Al (b) MAS NMR spectra of MZ-9

图6 传统ZSM-5和MZ-9样品的热重曲线

Fig. 6 Thermogravimetric analysis (TGA) curves of conventional ZSM-5 and MZ-9

图7 聚乙二醇作为介孔模板制备介孔ZSM-5沸石的机理示意图

Fig. 7 Proposed synthesis procedure of mesoporous ZSM-5 templated by PEG

图8 氢型传统ZSM-5和介孔沸石MZ-9的氨气-程序控温脱附曲线

Fig. 8 NH3-TPD profiles of conventional H-ZSM-5 and MZ-9

图9 苯甲醛与正丁醇的醇醛缩合反应(a)和间苯二酚与乙酰乙酸乙酯的佩希曼缩合反应(b)

Fig. 9 Aldol condensation of benzaldehyde and n-butyl alcohol (a) and Pechmann reaction of resorcinol with ethyl acetoacetate (b)

表2 MZ-9和传统ZSM-5沸石催化性能对比

Table 2 Catalytic properties of MZ-9 and conventional ZSM-5[a]

Reactions	MZ-9 (Si/Al=25)	Con ZSM-5 (Si/Al=25)
Benzaldehyde + n-butyl alcohol	43.3	19.1
Resorcinol+ethylacetoacetate	40.0	17.5

参考文献 47

[1]	DAVIS M E.Ordered porous materials for emerging applications.Nature, 2002, 417(6891): 813-821.
[2]	CORMA A.State of the art and future challenges of zeolites as catalysts.Journal of Catalysis, 2003, 216(1): 298-312.
[3]	TAO Y, KANOH H, ABRAMS L, et al.Mesopore modified zeolites: preparation, characterrization, and applications. Chemical Reviews, 2006, 106(3): 896-910.
[4]	PEREZ-RAMIREZ J, CHRISTENSEN C H, EGEBLAD K, et al.Hierarchical zeolites: enhanced utilisation of microporous crystals in catalysis by advances in materials design.Chemical Society Reviews, 2008, 37(11): 2530-2542.
[5]	LE HUA Z, ZHOU J, SHI J L.Recent advances in hierarchically structured zeolites: synthesis and material performances.Chemical Communications, 2011, 47(38): 10536-10547.
[6]	CHEN L H, LI X Y, ROOKE J C, et al.Hierarchically structured zeolites: synthesis, mass transport properties and applications.Journal of Materials Chemistry, 2012, 22(34): 17381-17403.
[7]	MOLLER K, BEIN T.Mesoporosity a new dimension for zeolites.Chemical Society Reviews, 2013, 42(9): 3689-3707.
[8]	SERRANO D P, ESCOLA J M, PIZARRO P.Synthesis strategies in the search for hierarchical zeolites.Chem. Soc. Rev., 2013, 42: 4004-4035.
[9]	HOFFMANN N.Photochemical reactions as key steps in organic synthesis.Chemical Reviews, 2008, 108(3): 1052-1103.
[10]	SOLER I G, SANCHEZ C, LEBEAU B, et al.Chemical strategies to design textured materials: from microporous and mesoporous oxides to nanonetworks and hierarchical structures.Chemical Reviews, 2002, 102(11): 4093-4138.
[11]	JANSSEN A H, KOSTER A J, DE Jong K P. Three-dimensional transmission electron microscopic observations of mesopores in dealuminated zeolite Y.Angewandte Chemie International Edition, 2001, 40(6): 1102-1104.
[12]	VAN D S, JANSSEN A H, BITTER J H, et al.Generation, characterization, and impact of mesopores in zeolite catalysts.Catalysis Reviews, 2003, 45(2): 297-319.
[13]	PEREZ R J, ABELLO S, VILLAESCUSA L A, et al.Toward functional clathrasils: size and composition controlled octadecasil nanocrystals by desilication.Angewandte Chemie International Edition, 2008, 47(41): 7913-7917.
[14]	CHEN L H, LI X Y, TIAN G, et al.Highly stable and reusable multimodal zeolite TS-1 based catalysts with hierarchically interconnected three level micro-meso-macroporous structure.Angewandte Chemie International Edition, 2011, 50(47): 11156-11161.
[15]	DING J, LIU H, YUAN P, et al.Catalytic properties of a hierarchical zeolite synthesized from a natural aluminosilicate mineral without the use of a secondary mesoscale template.Chem CatChem, 2013, 5(8): 2258-2269.
[16]	JACOBSEN C J H, MADSEN C, HOUZVICKA J, et al. Mesoporous zeolite single crystals.Journal of the American Chemical Society, 2000, 122(29): 7116-7117.
[17]	SCHMIDT I, BOISEN A, GUSTAVSSON E, et al.Carbon nanotube templated growth of mesoporous zeolite single crystals.Chemistry of Materials, 2001, 13(12): 4416-4418.
[18]	TAO Y, KANOH H, KANEKO K.ZSM-5 monolith of uniform mesoporous channels.Journal of the American Chemical Society, 2003, 125(20): 6044-6045.
[19]	KUSTOVA M, EGEBLAD K, ZHU K, et al.Versatile route to zeolite single crystals with controlled mesoporosity: in situ sugar decomposition for templating of hierarchical zeolites. Chemistry of Materials, 2007, 19(12): 2915-2917.
[20]	FAN W, SNYDER M A, KUMAR S, et al.Hierarchical nanofabrication of microporous crystals with ordered mesoporosity.Nature Materials, 2008, 7(12): 984-991.
[21]	CHOI M, CHO H S, SRIVASTAVA R, et al.Amphiphilic organosilane directed synthesis of crystalline zeolite with tunable mesoporosity.Nature Materials, 2006, 5(9): 718-723.
[22]	WANG H, PINNAVAIA T J.MFI zeolite with small and uniform intracrystal mesopores.Angewandte Chemie International Edition, 2006, 45(45): 7603-7606.
[23]	KIRSCHHOCK C E A, KREMER S P B, VERMANT J, et al. Design and synthesis of hierarchical materials from ordered zeolitic building units.Chemistry-a European Journal, 2005, 11(15): 4306-4313.
[24]	BERMEJO D R, GOUNDER R, DAVIS M E.Framework and extraframework tin sites in zeolite beta react glucose differently.ACS Catalysis, 2012, 2(12): 2705-2713.
[25]	WANG L, ZHANG Z, YIN C, et al.Hierarchical mesoporous zeolites with controllable mesoporosity templated from cationic polymers.Microporous and Mesoporous Materials, 2010, 131(1): 58-67.
[26]	ZHU Y, HUA Z, ZHOU J, et al.Hierarchical mesoporous zeolites: direct self-assembly synthesis in a conventional surfactant solution by kinetic control over the zeolite seed formation.Chemistry-A European Journal, 2011, 17(51): 14618-14627.
[27]	NA K, JO C, KIM J, et al.Directing zeolite structures into hierarchically nanoporous architectures.Science, 2011, 333(6040): 328-332.
[28]	LIU F, WILLHAMMAR T, WANG L, et al.ZSM-5 zeolite single crystals with b-axis-aligned mesoporous channels as an efficient catalyst for conversion of bulky organic molecules.Journal of the American Chemical Society, 2012, 134(10): 4557-4560.
[29]	MENG X, NAWAZ F, XIAO F S.Templating route for synthesizing mesoporous zeolites with improved catalytic properties.Nano Today, 2009, 4(4): 292-301.
[30]	HOLM M S, TAARNING E, EGEBLAD K, et al.Catalysis with hierarchical zeolites.Catalysis Today, 2011, 168(1): 3-16.
[31]	LIU Y, ZHANG W, LIU Z, et al.Direct observation of the mesopores in ZSM-5 zeolites with hierarchical porous structures by laser hyperpolarized 129Xe NMR.The Journal of Physical Chemistry C, 2008, 112(39): 15375-15381.
[32]	ZHU H, LIU Z, KONG D, et al.Synthesis of ZSM-5 with intracrystal or intercrystal mesopores by polyvinyl butyral templating method.Journal of Colloid and Interface Science, 2009, 331(2): 432-438.
[33]	TAO H, LI C, REN J, et al.Synthesis of mesoporous zeolite single crystals with cheap porogens.Journal of Solid State Chemistry, 2011, 184(7): 1820-1827.
[34]	ZHOU J, HUA Z, LIU Z, et al.Direct synthetic strategy of mesoporous ZSM-5 zeolites by using conventional block copolymer templates and the improved catalytic properties.ACS Catalysis, 2011, 1(4): 287-291.
[35]	NAKANISHI K.Pore structure control of silica gels based on phase separation.Journal of Porous Materials, 1997, 4(2): 67-112.
[36]	TAKAHASHI R, NAKANISHI K, SOGA N.Aggregation behavior of alkoxide-derived silica in Sol-Gel process in presence of poly (ethylene oxide).Journal of Sol-Gel Science and Technology, 2000, 17(1): 7-18.
[37]	TAKAHASHI R, SATO S, SODESAWA T, et al.Silica alumina catalyst with bimodal pore structure prepared by phase separation in Sol-Gel process.Journal of Catalysis, 2001, 200(1): 197-202.
[38]	SUN Q, BEELEN T P M, VAN Santen R A, et al. PEG-mediated silica pore formation monitored in situ by USAXS and SAXS: systems with properties resembling diatomaceous silica.The Journal of Physical Chemistry B, 2002, 106(44): 11539-11548.
[39]	CHEN G, JIANG L, WANG L, et al.Synthesis of mesoporous ZSM-5 by one-pot method in the presence of polyethylene glycol.Microporous and Mesoporous Materials, 2010, 134(1): 189-194.
[40]	TAO H, YANG H, LIU X, et al.Highly stable hierarchical ZSM-5 zeolite with intra and inter crystalline porous structures.Chemical Engineering Journal, 2013, 225: 686-694.
[41]	NAIK S P, CHIANG A S T, THOMPSON R W. Synthesis of zeolitic mesoporous materials by dry gel conversion under controlled humidity.The Journal of Physical Chemistry B, 2003, 107(29): 7006-7014.
[42]	DENG X, WANG Y, SHEN L, et al.Low-cost synthesis of titanium silicalite-1 (TS-1) with highly catalytic oxidation performance through a controlled hydrolysis process.Industrial & Engineering Chemistry Research, 2013, 52(3): 1190-1196.
[43]	ZHOU J, HUA Z, ZHAO J, et al.A micro/mesoporous aluminosilicate: key factors affecting framework crystallization during steam assisted synthesis and its catalytic property.Journal of Materials Chemistry, 2010, 20(32): 6764-6771.
[44]	GRANDI S, MAGISTRIS A, MUSTARELLI P, et al. Synthesis and characterization of SiO2-PEG hybrid materials. Journal of Non-crystalline Solids, 2006, 352(3): 273-280.
[45]	ZHOU J, LIU Z C, LI L Y, et al.Hierarchical mesoporous ZSM-5 zeolite with increased external surface acid sites and high catalytic performance in oxylene isomerization.Chinese Journal of Catalysis, 2013, 34(7): 1429-1433.
[46]	SHETTI V N, KIM J, SRIVASTAVA R, et al.Assessment of the mesopore wall catalytic activities of MFI zeolite with mesoporous/ microporous hierarchical structures.Journal of Catalysis, 2008, 254(2): 296-303.
[47]	HORNING E C, DENEKS M O, FIELD R E.3, 5-Dimethyl- 4-Carbethoxy-2-Cyclohexen-1-One and 3, 5-Dimethyl-2-Cyclohexen- 1-One. Organic Syntheses, 1955: 24.